Comparative anatomy of the brachial plexus and shoulder nerves of the Sapajus.

BACKGROUND The capuchin is a neotropical primate that presents easy reproduction in captivity and is used in scientific research. The objective of this work was to describe the structure and the branching pattern of the brachial plexus of the capuchin and to compare the results with data from the literature for humans, chimpanzees, baboons and Callithrix. METHODS Twelve specimens were used: eight males and four females. No animals were killed for the purpose of this study. RESULTS The brachial plexus of Sapajus sp was constituted mainly from the ventral roots of the last four cervical spinal nerves, from C5 to C8, mainly, and the first thoracic nerve (T1). CONCLUSIONS The pattern of formation of the brachial plexus of the capuchin monkey was more similar to that of Callithrix and baboons, perhaps because they are the only primates in this study to be essentially quadrupedal.